Sequential 242 Operation Manual

Midi interface cartridge for the commodore 64r

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MODEL 242

OPERATION MANUAL

^ E O U E fliiA L

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Page 1 MODEL 242 OPERATION MANUAL ^ E O U E fliiA L...
Page 2 SEQUENTIAL P ublications N umber: CM242A Publications D epartm ent Issued: O cto b er, 1984 MODEL 242 MIDI INTERFACE CARTRIDGE FOR THE COMMODORE 64R OPERATION MANUAL By Stanley Jungleib and Chet Wood Sequential Sequential POSTBUS 16 3051 North F irst S tr e e t...
Page 3 MODEL 242 MIDI INTERFACE CARTRIDGE FOR THE COMMODORE 64R OPERATION MANUAL By Stanley Jungleib and Chet Wood Com m odore 64 is a re g is te re d tra d e m a r k of C om m odore Business Machines, Inc.
Page 4: Table Of Contents
Table o f C ontents TOPIC PAGE OVERVIEW CONNECTION AND OPERATION Figure 1: C onnection D iagram HARDWARE OVERVIEW Figure 2: Block D iagram INTEGRATED CIRCUITS Figure 3: S ch em atic D iagram OTHER PARTS PROGRAMMING INTERRUPTS DRUM CLOCK INPUT OPTIONS Table 1: PIA C ontrol Modes Table 2: ACIA C ontrol Modes Table 3: PIA Addressing...
Page 5: Overview
C o n g ratu latio n s on your purchase of th e S equential C irc u its Model 242 MIDI c a rtrid g e for th e C om m odore 64 (C64). This c a rtrid g e ,...
Page 6: Connection And Operation
CONNECTION AND OPERATION CAUTION! Always sw itch power off to all equipm ent in use before conn ecting or disconnecting anything. O therw ise, serious d am ag e may resu lt to th e C64 or c a rtrid g e . MODEL >...
Page 7 2. Switch off power to th e C64, if it is not off alread y. 3. C arefully plug th e 242, fa c e up, into th e c a r tr id g e slot of th e C64.
Page 8: Hardware
HARDWARE The block diagram of th e 242 is shown below. Two m ain ICs a re used. The asynchronous co m m u nication s in t e r f a c e ad ap to r (ACIA) and its asso ciated bu ffer and o ptoiso lator tr a n s f e r MIDI serial d a ta to and from th e C64 d a t a bus.
Page 9: Integrated Circuits
Divides th e app ro x im ate ly 1 MHz C64 clock by two, supplying U105-3 and U105-4 w ith th e 500 KHz f r o n which th e 31.25 kBaud d a ta r a t e is derived (internally). CM 242 A...
Page 10 LAW USED DEtETED C 107 3051 N. FIRST ST. DO NOT SCA E ORAW ^ £ O U E r i u A L 0102 ^ C R O J i a i f K SAN JOSE.CA. 95134 Rl 14- TITLE UlOG>...
Page 11 DESIG. FUNCTION SCI PART // DESCRIPTION U104-6 Buffer 1-104 74LS08 Quad AND G ate Serial d a ta output from U105-6 drives U 104-4/5 and appears u ninverted a t U 104-6. When d a ta is low, c u rr e n t will flow from +5V through R103, th e e x te rn a l MIDI circ u it (which should be similar to th a t described above,...
Page 12: Other Parts
DESIG. FUNCTION SCI PART DESCRIPTION U106 1-064 6520 PIA The PIA tr a n s fe r s d a ta from th e S ta rt/S to p fo otsw itch and drum Clock inputs to th e C64 d a t a bus. Pins 26-33 co n n ec t to th e d a ta bus, CSO and CS1 a re tied high (active), and th e C64 co m m u n ic a te s w ith the PIA by addressing $DFXX, which puts a low on -CS2 (-1/02).
Page 13: Programming
This section gives an overview of program m ing th e 242, followed by exam ples in BASIC and in assem bly language. Using th e Model 242 is simply a m a tte r of reading and w riting to (in BASIC, PEEKing and POKEing) th e sev eral on-chip re g is te rs of the 6520 PIA and th e 6850 ACIA.
Page 14: Drum Clock Input Options
NOTE: The clock p olarity given in Table 1 r e f e r s to the input to the 242 c a r trid g e (J101), not th e input to th e PIA itse lf (U106-40). Table 1...
Page 15: Initialization
Initialization Both th e ACIA and th e PIA m ust be initialized a t pow er-up. The C64 addresses for th e re g iste rs re fe r re d to in th e t e x t can be found in Tables 3 and 4.
Page 16: Basic Program Example
The following exam ple can be used to com p letely check th e 242 and th e MIDI IN c irc u itry of the sy nthesizer. U n fo rtu n ate ly , since BASIC is so slow, th e MIDI OUT circ u itry of th e synth cann ot be checked.
Page 17 PRINTsPRINT "NOW CONNECT THE 242'S MIDI OUT " PRINT "TO MIDI IN OF THE SYNTH," PRINT "TURN SYNTH POWER ON," PRINT "AND WHEN THE SYNTH IS READY," PRINT "HIT ANY CHARACTER." PRINT " YOU SHOULD HEAR A GLISSANDO." GET A$ : IF A$="" THEN 339...
Page 18 1010 NEXT 1020 DD=DD/2 4(1/6) 1030 RETURN 1040 END 1990 REM SUBROUTINE TEST 242 MIDI HARDWARE 2000 PRINT "IF TEST NOT DONE IN 8 SECONDS," 2001 PRINT "HIT RUN/STOP RESTORE TO STOP PROGRAM," 2002 PRINT "THEN CHECK THE MIDI CABLE."...
Page 19: Programming In Assembly
PROGRAMMING IN ASSEMBLY LANGUAGE The following code segm ents illu s tra te th e program m ing principles described above. (To run them on th e C64, you need an assem bler and debugger.) 1. To initialize th e ACIA for MIDI: ;M aster r e s e t LDA #$03 STA $DE00...